1. Field of the Invention
This invention relates to a device for holding a tubular bushing assembly in place, and more particularly to a device for preventing a tubular bushing assembly from slipping out of a given position, when the tubular bushing assembly is incorporated, as a vibration isolator, in each pivot coupling portion in a vehicle body.
2. Description of the Prior Art
Some of the known tubular bushing assemblies of the type is incorporated into a pivot coupling portion between a suspension member of a trailing-arm-type wheel suspension system and a vehicle body. This type tubular bushing assembly includes an inner sleeve for receiving therein a pivot extending downward from the vehicle body, a tubular resilient member for receiving therein the inner sleeve and attached thereto, and an outer sleeve for receiving therein the resilient member and attached thereto. Each bushing assembly is fitted under pressure into respective bushing attaching portion provided in the suspension member, with the outer sleeve fitted into a hole provided in each bushing attaching portion, so that the bushing assembly is held in place in the bushing attaching portion by the frictional force of the outer sleeve relative to the bushing receiving portion.
Accordingly, should an external force stronger than the frictional force act on the outer sleeve in the axial direction thereof, the bushing assembly would slip out of the bushing attaching portion. With a view to preventing such a bushing assembly from slipping out of the bushing attaching portion, an attempt has been proposed, in which a diametrically outwardly projecting projection is formed on the outer sleeve and a recess engageable with the projection is provided in the inner peripheral wall of the hole in the bushing attaching portion, so that the bushing assembly can be retained in place by the so-called sliding fit of the projection into the recess in the wall of the hole. The sliding fit, however, can not completely prevent the slipping out of the bushing assembly. In order to fit under pressure the bushing assembly into the bushing attaching portion, a large force is needed. The bushing attaching portion must have a strength large enough to resist such a large force.
Another tubular bushing assembly of the known tubular bushing assemblies has been such that the outer sleeve of the bushing assembly consists of a pair of arcuate members, in order to permit compression in the diametrical direction of the resilient member. This type tubular bushing assembly is fitted under pressure into the hole in the bushing attaching portion, with the resilient member diametrically compressed between and within the pair of arcuate members. The frictional force of the outer sleeve, namely, respective arcuate members, relative to the bushing attaching portion is dependent on the resilient repulsion force of the resilient member. Accordingly, the tubular bushing assembly having an outer sleeve consisting of the pair of arcuate members is liable to slip out of the bushing attaching portion.